Credit cards, identification cards, security system cards, and the like are thin, small objects that are easily misplaced, lost, or stolen. With the advent of integrated circuits, even calculators, some of which have scientific applications, are quite thin and fit into a wallet or purse.
These credit cards, security system cards, or other devices are becoming smaller, thinner, and more common. They represent either money spent by the holder for these devices or, quite often, as in the case of credit cards, money that may be spent by the holder. All of these devices are valuable to one degree or another and can create problems for the holder if they are lost or stolen.
The present device relates to radio frequency proximity sensor apparatus and, in particular, relates to credit-card sized, radio frequency proximity sensor apparatus, such that the device may be conveniently carried in a wallet or purse. One part of the device is carried in the wallet or purse, or item to be protected; and the other part of the device is carried, for example, on a belt such that if the wallet or purse is moved away from the party using the inventive apparatus, an alarm will sound.
The device is adaptable to a wide variety of sensor proximity applications, such as wherein the receiver component of the device is attached to portable stereos, coats, briefcases, and luggage for the protection and the securement of same.